Water obtained from underground wells and other sources, or when air enters a city water supply, often contain large amounts of dissolved air. While there are many tests that can be performed to determine the amount of dissolved air, as by measuring the reaction of the oxygen in the dissolved air, these tests are cumbersome. Air dissolved in water can have many effects, such as producing uneven water "spitting" or spraying and noise when the water pressure is reduced, as when the water exits to the atmosphere. A simple apparatus and method for indicating the presence of significant amounts of dissolved air and/or indicating the amount of dissolved air in water, would be of value.